Endless belt aligning means



Oct. 17, 1950 G. A. LYON 2,526,033

ENDLEss BELT ALIGNING MEANS Filed Feb. 26, 1947 2 Shee'cs-Shee'rI lEg? 1. Eg Z E "s i;

l L l zo /9 m g Z7 3;/9 27 \Z7 ZZ 7 2] fx l 4%' 0 i; 42 t 45 FNZZ 4/ l:ZITZEH Z al" Oct. 17, 1950 Q A, LYON 252,033

ENDLESS BELT ALIGNING MEANS Filed Feb.v26, 1947 2 Sheets-Sheet 2 l. 'o"v t l l x s I i @k2/ay Engg.:

Patented ct. 1.7,

ENDLEss BELT ALIGNING MEANS George Albert Lyon, Detroit,A Mich.Application February 26, 1947, serial No. 731,028 claims. iol. 'i4-241)This invention relates to improvements in the control of endless beltsrunning over unanged rollers from which the belts may tend to creepedgewise but with which the belts must be maintained in alignment forproper results in operation.

An important object of the present invention is to provide improvedmeans which will respond to shifting from alignment of a running endlessbelt to return the belt to proper alignment.

Another objectof theinvention is to provide novel electrical controlmeans for operating a belt aligning device. i

A further object of the invention is to` provide novel electricallyactuated belt aligning means automatically operative in response tomisalignment of the belt with which associated. y

Still another object of the inventionfis to proward either side, thealignment members cooperating to restrain the belt against over-shiftingduring realignment opera tions.

Other objects, features and advantages of the present invention will bereadily apparent from the following detailed description of a preferredembodiment thereof taken in conjunction with the accompanying drawingsin which:

Figure l is a more or less schematic front elevational view of a machineutilizing endless belts and having belt aligning means according to thepresent invention;

vide means for automatically maintaining cooperative endless belts inproper running alignment.

According to the general features of the invention, there is provided inassociation with an endless belt to be maintained in a particularalignment a follower which is located to be actuated by the edge of thebelt adjacent to .the point where the belt is liable to shift out ofalignment,

and a belt aligner located at a point remote from the follower andresponsive to actuation ofthe follower to engage and effect realignmentmovement of the belt.

According to other general features of the invention the follower andthe belt aligner are connected in an electrical circuit under thecontrol of the follower.

According to further general features of the invention, there isprovided in a belt aligning device a follower movable by the edge of thebelt and a switch located to be actuated by movement of the followerresponsive to actuation by the edge of the belt for closing'anelectrical belt aligner circuit.

According to still other general features of the invention, a beltaligner'is provided which normally remains free from the belt with whichit Y is associated but is adapted to effect realignment operable forreturning the belt to lproper alignment when the belt moves out ofalignment to- Figure 2 is a side elevational view of the machine shownin Figure 1 Figure 3 is an enlarged horizontal sectional view takensubstantially along the line III- III of Figure 1;

Figure 4 is a fragmentary enlarged side elevational view of one of thebelt-edge follower controls of the belt aligning means, and

Figure 5 is a horizontal sectional view taken substantially on Jthe lineV-V of Figure 4.

As shown on the drawings:

An apparatus with which the belt aligning system or means of the presentinvention is particularly useful comprises a plastic sheet formingmachine as shown more or less schematically in Figs. l and 2. In such amachine plastic material in a fluid state is supplied from an extruderI0 between a pair of endless forming belts II which may be made fromstainless steel. The forming belts II are supported to run vertically byrespective combined driving, heating and pressure rolls I2 which aresupportedv rotatably in journals I3 carried by the top of a supportingframework I4. Power for driving the rolls I2 towards one another inunison is derived from a motor I5 operating through a gear reduction de-Vice I'I and a train of gears I 3 connected with the roll shafts.

4,The belts II are held stretched, and are separated from one another atthe lower ends of their -reaches to release the formed plastic sheet,

through the action of free weighting and separating rolls I9 which maybe of ring form. Each of the rolls I9 is formed with a pair of radiallyoutwardly extending annular flanges 2i! at the respective edges of itsperiphery. These flanges are adapted to ride against the similar flangesof the companion weighting and separating roll and maintain thebelt-engaging peripheries of the rolls in spaced relation at theirpoints of closest approach, thereby separating the forming reaches ofthe belts for releasing the formed 3 plastic preparatory to return ofthe belts to the heating and pressure rolls i2.

In view or" the close spacing which must prevail between the formingbelts ii at the point of entry of the plastic material therebetween,that is at the point of nearest approach of the pressure and heatingrolls i2, it is impractical to have the rolls i2 equipped with guideiianges which would keep the respective belts ii centered or alignedwith the rolls and with respect to each other. The peripheries aretherefore yiindrical.

Hence, any inaccuracies in belt tension or erioansion or contraction,deviation from absolutely horizontal parallelism of the axes ci therolls l2, slight inaccuracies in the concentricities' of the cylindricalperipheries of the rolls, and the like, tends to cause the belts H tocreep out of. alignment in the course of operation.. That is, one or theother, or both of the belts ii may work over toward and project edgewisebeyond the side of the roll I2 over which it is trained. rihis isYhighly objectionable, of course, because for proper torming or" theplastic between the belts and uniformity of surface plane, uniformpressure must be applied thereto throughout the width of the belts andthe belts must make full contact over the whole width of the formedplastic sheet. Since the reaches of the forming belts may be many feetin length, in a typical installation attaining to over eet, it will beappreciated that this matter of maintaining the belts in alignmentpresents a considerable problem.

4 28 in the biasing blocks 22 and have the periph cries thereofprojecting beyond the forward ends of the blocks, adequately clear theouter sides .0f

According to the present invention, the forining belts il are etectivelymaintained in operative alignment by utilizing the tendency of a belt tocreep edgewise in the direction of biasing twist thereon, and moreespecially a twist imparted to the return run or reach thereof, that isthe reach which is traveling toward the roller over which the belt istrained. For this purpose, a selectively operable biasing device 2i(Fig. 3) is cooperatively disposed at each side ci the lower end portionof the return reach of each of the forming belts ii. The biasing devicesiii are so constructed and arranged that when it becomes desirable torealign the belt ii with which it is associated, the return reach of thebelt will be appropriately twistingly deflected from its normal path tobias the same toward the side toward which the belt mus be shifted forrealignment.

Each of the biasing devices 2i is a unit including a movable biasingblock 22 mounted in a 23 upon a carriage 24 including a framework 25(Figs. 1 and 2). The carriage 2:3 is disposed at height and in suchlocation that the end of the track 23 is in spaced adjacent relation tothe rim of the associated weighting roll near the point where the returnstretch of the belt i leaves the roll. y

When the biasing block 22 is actuated to move it outwardly in its track23 to project beyond the track, an anti-friction roller 2l carried bythe block engages the side of the weighting roll and pushes the latterlaterally. This causes the roll to swing about a vertical axis andtwists the return stretch of the belt il to impart a thereto in thedirection of the corrective shitting of the belt desired. K

As seen in Figure 3,*the biasing devices 2i are disposed in directlyopposed relation at opposite sides of the rims of the respectiveweighting rolls i9, and in the inactive or retracted positions of thebiasing blocks they leave the weighting `roll entirely freetherebetween. The anti-friction rollers 2, which are disposed inrespective slots the blocks for operative engagement with the rims 0i"the Weighting rolls ii). In the fully retracted positions of the biasingblocks 22, the anti-friction rollers 2l are adapted to project beyondthe ends of the respective tracks E3 and serve as anti-friction buffersor stops to limit swinging or deflection of the weighting rolls i9either due to the biasing action of the opposing biasing block or due toany other cause. This relationship is best exemplified at le'"t side ofFigure 3.

Means are provided for rendering the biasing blocks 2&3 selectivelyactive for belt deection automatically when the belt l i controlledthereby shifts beyond a predeterl. ined limit from its op erative path.Since the deilection tolerances for the belts ii must necessarily befairly close, the alignment control system must be Vreasonablysensitive. Herein the control include a detector unit 53.9 disposed ateach edge o return stretch of each of the belts il as close as practincable to the point where the respective belts engage the pressure rollsi2, that s, adjacent to the extreme upper ends of the return stretchesof the belts.

As best seen in Figures 4 and 5, each oi the detector units 29 includesa shoe si in engag ent with the edge of the belt and replaceably earnedby a bracket 3i. The latter has a cantilever sa. port arm reciprocablysiidable in a carriage s3 attached by means of bolts -i to the frame Eilincluding a pair of parallel bars d forming a track or slideway for thearms The shoe Sii is normally urged into engagement with the edge of thebelt il by means coiled tension spring 3l which acts agah inner end oithe arm and bears against a ticnary angle plate 38.

Extending beyond the inner end of the 52 is a switch-operating pins@which projects freely through the angle plate @t and is adapted tc closea normally open limit or micro-switch housed in a casing lil supportedby the angle plate. .es shown in Figure 4, the switch may have operatingbutton il adapted to be actuated by t adjacent end of the pin uponrelative" c inward movement of the detector shoe sulting from shiftingof the beit i i from its operative path.

Upon closing or the normally open sw' oh in the housing iii), anelectrical circuit S is closed to energize a Xedly mounted solenoid d2of the companion biasing device 2i. This causes an armature secured tothe biasing block 22 to drive the block outwardly on its track toproject therebeyond Aand deiiect the associated weighting roll iS andthus thebelL ii. As soon as the belt Il has shifted back to its properpath, the shoe 3G, of course, follows the edge of the belt under theinfluence of the spring 3l and the switch operating pin 39 is releasedfrom the switch operator which promptly opens and breaks the electricalcircuit S and deenergizes the solenoid 42. Immediately upon suchdeenergization of the solenoid s2, a return spring fifi acting upon ahead le at the outer free end of the armature 43 draws the armaturethrough the solenoid and returns the biasing block 22 to its inactiveposition. Y

It will thus be apparent that both of the forming belts il, will as aresult of the sensitive, automatic detector and biasing devices 29 inthe "otherwise than necessitated `effraie-033 beltalfgningfsystmne*maintainednl; alrnnles ln f3 Y Vproperali'g'nme'ntAwithin very close limits.

` It will,l of course, be understood rthat various v'"details"bi"construction may be varied 'through 4a wide'rang'e' without 'departingfrom the principles of this inventiorrand itis, therefore, not thepurpose to limit the'p'atent grantedfhereon by the scope of the appendedclaims. 1 I claim Vas my invention a Ypredeter'lriined.pathincluding' a'reciprocable 'member selectivelyengageable'with the 'side of A carrying-rmembers selectively, thef respective;

,"roller's being disposedV in the inactive condition y of therespectivebiasing units Yto llimit the de- Y ilection movement of the belt underthe inuence Y of the opposite biasing unit when the roller carryingmember Athereof is actuated by said actu- ,6.V 1n an endless beltinstallation including an unilanged driving roll having 'an endless belttrainedgthereover and depending therefromwith the lower loop of the beltsupporting a flangedv 'tensioni-ngroll freely therein, the belt beingsubjectjto shifting-axially of the supporting and` drivingroll--inrunning thereove'r,a'belt aligning lmember movable in an axial directionrelative said tensioning roll vto "delectthe same for vbiasfg, ing thebelt to return the belt to said'pedejf" terniined path' when the beltshifts from said path during running thereof and means for actuatingsaid member.V

2. In comblnationlwltn a machine including an endless belt travelingrthrough a relatively long return reach in a vertical plane andsupporting a tensioning roll" in the "lower'turn of the belt, means for;maintaining thejbelt in a predetermined pathincluding a memberengageable i endless belt depending from an unflanged driving with theVside 'of said tensioning roll to deflect means for actuating saidmember, said'member being in the form of a reciprocably guided blockhaving anti-friction means thereon for contactg ing the tensioning roll.3. In combination4 with a machine including an endless belt travelingthrough a relatively tot said"ten'sioning roll and arranged tol rideagainst the side of the tensioning 'roll for pushingtheftensioning lrollto ltwist it .from its'normally Vsuspended -positicnas carriedby...the.;.belt

so as to d'eilect and bias the belt `for re'alig'ning uljjit-n saidsupporting and driving roll, and means located at the side of 'the beltadjacent to where -the belt runs'over v'the supporting and driving rollfor detecting misalignment of the belt and connected with said aligningmember forcen- V trollingthe latter.

long return reach in a vertical plane and sup-" porting la tensioningroll in the lower turn of the belt, means for maintaining the belt in avof, means foractuating said member, and a detector'unit associated withthe upper end of the .return reachof Vthe belt' for detecting deviationfrom the predeterminedpath and operably con` -'7. Inan endless-beltassembly including an roll Afand having a'f'reelysupported flangedtensioning roll in thelower loop of Vthe belt substantially below theunflan'fged supporting and driving roll, aY detector member at each edgeof the returnrun ofthe belt closely adjacent to the Isupporting anddriving roll for' detecting shifting out of alignment of the belt in itsplane in either axial direction relative to said roll, and corre-'spending belt aligners located at opposite sides of the tensioning rolladjacent the trailing end of the return run of the belt and operablyconnected with the respective corresponding detectors to be actuated inresponse to misalignment i 'movementtoward either of the detectors topush against the respective side of the tensioning roll for biasing theb elt and returning the same to properY alignment with the supportingand driving roll.

8. In a plastic sheet forming machine includl ing a pair of cooperatingopposed forming rolls,

nected with the actuating means for said biasing member to control the'operation of the ff same. l

4. In combination with an endless metal belt running over a dri-ven rollyanddepending there- 7.-"

from, the belt being maintained under tension an endless forming belt'suspended from and running over eachof the rolls with the adjacentrollsso las to carry a formed plastic sheet downf wardly therebetween,each of the belts having a by a tensioning roll suspended in the lowerloop-- ofthe belt,"and means for maintaining the belt aligned on saiddriven roll including a selectively7 operable member engageable vwithsaid-tensioning roll tov deflect the same and impart a shifting bias tothe belt.

5, In combination with a traveling belt trained over an unflanged rolland having a return stretch of substantial length, the belt beingsubject to shifting from a predetermined operative path due toinaccuracies in the roll or in the belt and lack of holding flanges onthe roll, a pair of belt biasing units respectively disposed adjacent tothe opposite sides of the trailing end portion of the return stretch ofthe belt and 'each including a member carrying an anti-friction roller,each of said roller carrying members being mounted for movement towardthe belt for deflecting the belt toward the other of said biasfreelysupported flanged tensioning roll in the Alower loop-of the belt,saidforming rolls having y turning each respective belt to properalignment when it runs out of alignment toward either end of its formingand carrying roll includinga deg" unitsf iand means "for actuatlngilsaid.roller for returning the belts to alignment in the event Alof deviationfrom proper alignment.

9. In a plastic `forming machine including a 1' pair of uniiangedforming rolls in closely adja- ,between the lower portions of thedownward runs of the belts, means for maintaining the belts in properalignment on said forming rolls comprising a reciprocable memberadjacent to each side of each of the tensioning rolls adjacent to thetrailing end of the return run of the respective belt supporting thetensioning rolls, and means for actuating said aligning membersselectively to push againstv the respective adjacent sides of thetensioning roll to swing the roll from its normal axis and thereby biasthe return run of the belt to return to proper alignment.

10. In combination in a belt aligning device of the type adapted toengage the freely supported tensioning roll of a suspended endless beltto twist the tensioning roll from its normal axis for realignmentbiasing of the belt, a sup-porting structure, a horizontal guideway yonsaid supporting structure, a block -slidably guided by said guideway, ananti-friction roller having the periphery thereof projecting beyond anend of the block, and means at the opposite end of the block for'selectively moving said block reciprocably in said guideway forengagement of or retraction from the side of the tensioning roll. y

1l. In a belt aligning system, a detector construction comprising asupport providing a longitudinal guideway, a belt edge engaging shoehaving a cantilever support arm reciprocably mounted in said guideway,means normally biasing the support arm in one direction in said guidewayto carry the shoe into engagement with the edge of the belt, a switchoperating pin extending from said opposite end of said arm, and anelectrical switch adapted to be operated by said pin upon movement ofsaid shoe and arm by the belt in opposition to the biasing means forclosing an electrical actuating circuit for means such as a beltaligner.

12. In combination in a belt aligning construction, a reciprocable beltedge follower serving as a detector, an electric switch normally openand arranged to be closed by said follower upon movement ci" an engagedbelt out of alignment, and a belt aligner member including a solenoid incircuit with said switch and a connection between the aligner member andthe solenoid for effecting projectionof said aligner member toward thebelt to be aligned upon closing of said switch and energizing of thesolenoid.

13. In an endless belt installation wherein an endless'belt running overan unflanged roll depends freely from said roll and has in the lowerloop thereof a Banged tensioning roll freely supported by the belt, apair of belt aligning members, means supporting Asaid' members in spacedopposition at respective opposite sides ci the tensioning r'oll and inspaced relation thereto adjacent to the return run of the belt whichsupports the tensioning roll 'and with the roll and belt suspendedfreely between said members, means carried by said respective supportsfor selectively actuating said members into engagement with the opposingsides of the tensioning roll for pushing the tensioning roll therefromto bias the belt for realignment, and detector means associated withtheupper portion of the return run Yof the belt for detecting anymisalignment of the belt and selectively actuating said aligners. v f

14. In apparatus for eiecting realignment of an endless belt which issuspended from a driving roll and has a freely supported tensioning rollcarried thereby in the lower loop of the belt, means for pushing againstthe side of the tenioning roll adjacent to the trailing end of thereturn run of the rbelt to twist the tensioning roll from its normaloperating axis and thereby biasing the return run of the belt in thedirection of desired realignment movement of the belt onsaid supportingand driving roll, and means for actuating said pushing means whenrthebelt requires realignment.

'15. In apparatus forl maintaining a pair of endless forming belts inproper alignment with respect to each other and to a pair or beltsupporting and forming rolls over which the belts are trained and fromwhich they are suspended, the

forming rolls lacking belt retaining ilanges, the belts having freelysupported tensioning rolls carried by lthe lower loops of the belts andwith retaining flanges riding together for separating the downward runsof the belts, means for tilting either` oi the tensioning rolls relativeto the other tensioning roll to bias the return run of the beltsupporting the tilted roll for returning the biased belt into properalignment whenever it runs out of alignment, and means for actuatingsaid tilting means when the respective belts require realignment.

GEORGE ALBERT LYON.

REFERENCES @FEED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Hill Aug. 13, 1940

